PET precursor films with the thickness of 260 μm were provided by Guofeng Plastic Industry Co., Ltd with an intrinsic viscosity of 0.65 dl/g, corresponding to a viscosity molecular weight of 18069 g/mol. The glass-transition temperature (Tg), the cold crystallization temperature (Tc), and the melting point (Tm) were measured to be 72.4 °C, 124.8 °C and 255.0 °C, respectively, with differential scanning calorimetry (DSC; Q2000, TA Instruments) at a rate of 10 °C/min. During the production of the precursor film, the PET melt was fast chilled down after extruded out from slit die, during which the drawing of polymer melt was inevitable.